Infrared camera and method for calculating output power value indicative of an amount of energy dissipated in an image view

ABSTRACT

An IR camera includes a thermal radiation capturing arrangement for capturing thermal radiation of an imaged view in response to input control unit(s) receiving user inputs from a user of the IR camera; a processing unit arranged to process the thermal radiation data in order for the thermal radiation data to be displayed by an IR camera display as thermal images; and an IR camera display arranged to display thermal images to a user of the IR camera. The processing unit is further arranged to determine at least one temperature reference value representing the temperature of the surrounding environment of the imaged view; and calculate at least one output power value indicative of an amount of energy dissipated in a part of the imaged view by using the temperature value of the thermal radiation data corresponding to said part of the imaged view and the at least one determined temperature reference value.

TECHNICAL FIELD

The present technology relates in general to IR cameras and methods foruse in a processing unit of IR cameras, in particular to IR camera andmethods for capturing IR radiation data of an imaged view.

BACKGROUND

Infrared (IR) thermal cameras can be used in a number of differentsituations, for example, when inspecting or surveying complex electricalsystems such as transformers, switchgears etc., or water carryingsystems such as heat exchangers, radiators etc. IR cameras are used forcapturing and storing thermal radiation data. This thermal radiationdata may then be displayed and viewed as thermal images and analyzed inorder to, for example, find faulty electrical wirings or couplings,leaking water pipes, etc.

However, various procedures and methods are being used in order toproperly analyse the thermal radiation data and/or the thermal images ofthe IR camera, and these are not necessarily particularly intuitive andeasily understandable by a user of the IR camera. The analysis of thethermal radiation data and/or the thermal images of an IR camera mayalso be a time-consuming task and may thus preclude a user of an IRcamera from making decisions, predictions, and/or recommendations toclients while being on site and performing the IR imaging.

SUMMARY

Accordingly, there is a need to provide an IR camera with increasedusability when analysing thermal images.

In order to solve the above-mentioned and other problems, in anexemplary embodiment, an IR camera comprises: a thermal radiationcapturing arrangement for capturing thermal radiation of an imaged viewin response to an input control unit(s) receiving inputs from a user ofthe IR camera; a processing unit arranged to process the thermalradiation data in order for the thermal radiation data to be displayedby an IR camera display as thermal images; and an IR camera displayarranged to display thermal images to a user of the IR camera. Theprocessing unit of the IR camera may be further arranged to: determineat least one temperature reference value representing the temperature ofthe surrounding environment of the imaged view; and calculate at leastoutput power value indicative of an amount of energy dissipated in apart of the imaged view by using the temperature value of the thermalradiation data corresponding to said part of the imaged view and the atleast one determined temperature reference value.

The exemplary embodiment may increase usability to a user of an IRcamera when analysing the thermal images of the IR camera by enabling acalculation of the output power dissipated in an imaged view. This alsoallows a user of the IR camera to achieve an estimate of the energyproperties of an imaged view in a simple and easy manner.

The processing unit of the IR camera may also be arranged to control theIR camera display to display the at least one calculated output powervalue to a user of the IR camera in place of the correspondingtemperature pixel in the thermal image. This enables the user of the IRcamera to monitor the outputted power density of the energy radiatingfrom an imaged view directly in the IR camera display as the object isbeing imaged by the IR camera.

The processing unit of the IR camera may also be arranged to determine afirst subset of the thermal radiation data as a thermal image objectarea representing an object in the imaged view for which an output powervalue is to be determined; and calculate an object output power valueindicative of the amount of energy outputted from the object in theimaged view based upon output power values of the determined thermalimage object area in the thermal radiation data. This may provideincreased usability to a user of an IR camera when analysing the thermalimages of the IR camera by enabling a calculation of the output powerradiating from an object in an imaged view. This also allows a user ofthe IR camera to achieve an estimate of the energy properties of animaged object in a simple and easy manner.

The processing unit of the IR camera may also be arranged to control theIR camera display to display the calculated object output power value toa user of the IR camera together with the thermal images. This enablesthe user of the IR camera to monitor the output power radiating from anobject directly in the IR camera display as the object is being imagedby the IR camera. The processing unit of the IR camera may also bearranged to receive information comprising current energy priceinformation and time span information. This may be performed by the userof the IR camera using the input control devices. By being furtherarranged to calculate the energy outputted by the object in the imagedview based on this time span information and the object output powervalue, an estimated cost of the total energy consumption may be based onthe received current energy price information and the outputted energy.This cost estimate may then be displayed by the IR camera display to theuser of the IR camera together with the thermal images, such that a fastand efficient energy cost evaluation for the object may be performedimmediately on site.

The processing unit of the IR camera may further be arranged todetermine the thermal image object area in the thermal radiation data byreceiving information from the input control unit(s) indicating a subsetof the thermal radiation data as the thermal image object area. Thisallows a user of the IR camera to manually indicate an area in thedisplayed IR thermal images of the IR camera display representing theobject for which the user of the IR camera desires the output power tobe determined; the indicated area will correlate to a particular subsetof the thermal radiation data. While this alleviates the need for anythermal image segmentation to be performed automatically by the IRcamera, an area representing the object for which the user of the IRcamera desires the output power to be determined may also be establishedusing a temperature threshold value. This enables the IR camera toautomatically identify a subset of the thermal radiation data as thethermal image object area.

Furthermore, the processing unit of the IR camera may be arranged toreceive information from the input control unit(s) comprising a value ofthe actual physical surface area of the object in the imaged view facingtowards the IR camera, whereby this area value may be used whencalculating the object output power value. This alleviates the need foran object area estimation to be performed automatically by the IRcamera. The processing unit of the IR camera may also be arranged toreceive information from a distance determining unit comprised in the IRcamera which comprises the distance between the actual physical objectcaptured in the imaged view and the IR camera, determine an objectfield-of-view of the determined thermal image object area in the thermalradiation data, estimate the actual physical surface area of the objectin the imaged view facing towards the IR camera based upon the receiveddistance and the determined object field-of-view, and use thisestimation when calculating the object output power value. This enablesthe IR camera to automatically estimate the actual physical surface areaof the object in the imaged view facing towards the IR camera.

Additionally, the processing unit of the IR camera may be arranged toreceive information from the input control unit(s) comprising a formindicator which is indicative of the shape or form of the actualphysical object in the imaged view, and use this form indicator or acorresponding value when calculating the object output power value. Thisenables the IR camera to use the object output power value calculatedusing the estimate of the actual physical surface area of the objectfacing towards the IR camera for estimating a total object output powervalue for the entire physical object by taking actual physical surfaceareas of the object not visible in the imaged view into consideration inthe power calculation. The processing unit of the IR camera may also bearranged to, when the distance comprised in the information from thedistance determining unit is a distance map comprising separate distancevalues for different subsets of the thermal radiation data, estimate theshape or form of the actual physical object in the imaged view using thedistance map, and use this estimate when calculating the object outputpower value. This enables the IR camera to more accurately estimateactual physical surface areas of the object in the imaged view, andconsequently estimating an improved total object output power value forthe entire physical object viewed.

The processing unit of the IR camera may furthermore be arranged todetermine the at least one temperature reference value by receivinginformation from the input control unit(s) comprising a temperaturevalue(s) to be used as the at least one temperature reference value.This allows a user of the IR camera to input the at least onetemperature reference value into the IR camera manually. The processingunit of the IR camera may also be arranged to determine a thermal imagereference area in the thermal radiation data that is not part of thedetermined thermal image object area in the thermal radiation data,calculate an representative temperature value for the thermal imagereference area in the thermal radiation data, and using therepresentative temperature value for the thermal image reference area inthe thermal radiation data as the at least one temperature referencevalue when determining the at least one temperature reference value.Alternatively, the processing unit of the IR camera may be arranged todetermine the at least one temperature reference value by receivingtemperature value(s) from at least one temperature measurement unit(s)comprised in the IR camera. The two latter features allows the IR camerato automatically determine the at least one temperature reference valueto be used in the power calculations.

According to another exemplary embodiment, a method for use in aprocessing unit of an IR camera capturing thermal radiation data of animaged view is provided. The method may comprise: determining a subsetof the thermal radiation data as a thermal image object arearepresenting an object in the imaged view for which an output powervalue is to be determined; determining at least one temperaturereference value representing the temperature of the surroundingenvironment of the object in the imaged view; and calculating an objectoutput power value indicative of the amount of energy dissipated fromthe object in the imaged view based upon the determined thermal imageobject area in the thermal radiation data, and the at least onedetermined temperature reference value.

The method may further comprise: controlling the IR camera display todisplay the calculated object output power value to a user of the IRcamera together with the thermal images. Alternatively, the method mayalso comprise: receiving information comprising current energy priceinformation and time span information, calculating a total energy outputvalue for the object in the imaged view based on the time spaninformation and the calculated object output power value, calculating atotal energy cost value based on the current energy price informationand the total energy output value, and controlling the IR camera displayto display total energy cost value to a user of the IR camera togetherwith the thermal images.

According to yet another exemplary embodiment, a computer programproduct for use in an IR camera is provided, which comprises computerexecutable instructions that, when run in a processing unit in the IRcamera cause the processing unit in the IR camera to: determine a subsetof the thermal radiation data captured by the IR camera as a thermalimage object area representing an object in the imaged view for which anoutput power value is to be determined; determine at least onetemperature reference value representing the temperature of thesurrounding environment of the object in the imaged view; and calculatean object output power value indicative of the amount of energyoutputted from the object in the imaged view based upon the determinedthermal image object area in the thermal radiation data, and the atleast one determined temperature reference value.

Further embodiments of the IR camera, the method, and the computerprogram product are set forth in the dependent claims and the rest ofthe specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an IR camera according to an embodiment.

FIG. 2 shows an exemplary operation of an IR camera according to anembodiment.

FIG. 3 shows another exemplary operation of an IR camera according to anembodiment.

FIG. 4 shows further exemplary operation of an IR camera according to anembodiment.

FIG. 5 is a flowchart illustrating a method according to an exemplaryembodiment.

FIG. 6 is a flowchart illustrating a method according to an exemplaryembodiment.

FIG. 7 is a flowchart illustrating a method according to an exemplaryembodiment.

DETAILED DESCRIPTION

FIG. 1 shows an IR camera 1 according to an exemplary embodiment. The IRcamera 1 may capture thermal radiation of an imaged view 2 in responseto receiving inputs from a user of the IR camera 1, and present thethermal radiation in the form of thermal images to a user of the IRcamera 1 via an IR camera display 11. The IR camera 1 may comprise athermal radiation capturing arrangement for capturing thermal radiationcomprising at least one lens arrangement 4, a detector element 5 and asignal conditioning unit 6. The incoming radiation to the IR camera 1 isfocused by at least one lens arrangement 4 onto the detector element 5.The detector element 5 may typically be a matrix of detector elements,each of which may detect radiation from a corresponding area, forexample, a wall, water pipes, electrical connectors, etc., that is beingimaged. The detector element 5 may, for example, be a focal plane array(FPA).

From the detector element 5, captured thermal radiation data T_(x,y) maybe fed to a signal comprising signal values to a signal conditioningunit 6. The signal conditioning unit 6 may perform conventional signalconditioning, such as, for example, corrections for the inherent offset,gain drift, etc, and convert the signal values into thermal radiationdata T_(x,y) comprising temperature values. The signal conditioning unit6 is arranged to output a thermal radiation signal comprising thethermal radiation data T_(x,y) to a processing unit 7.

The processing unit 7 is arranged to receive the thermal radiationsignal comprising the thermal radiation data T_(x,y) from the signalconditioning unit 6. The processing unit 7 is also arranged to controlan IR camera display 11, for example, a viewfinder, a digital displayand/or touch screen provided on the IR camera housing. The processingunit 7 is further arranged to process the thermal radiation data T_(x,y)in order for the thermal radiation data T_(x,y) to be displayed by theIR camera display 11 as thermal images. The processing unit 7 may outputa thermal image signal to the IR camera display 11. The thermal imagesignal to the IR camera display 11 may also comprise additionalinformation other than the thermal images to be displayed by the IRcamera display 11. The thermal radiation data recorded by the IR camera1 can thus controlled to be displayed in the IR camera display 11 asthermal images, with or without the additional information, and bepresented to a user of the IR camera 1. The operation of the processingunit 7 in the IR camera 1 is described in more detail in the exemplaryembodiments presented below with reference to FIGS. 2-5.

It should be noted that the signal conditioning unit 6 and theprocessing unit 7 may be provided as one physical unit, or alternativelyas a plurality of logically interconnected units. The signalconditioning unit 6 and the processing unit 7 may also compriseprocessing means or logic for performing the functionality of the IRcamera 1. This functionality may be implemented partly by means of asoftware or computer program. The signal conditioning unit 6 and theprocessing unit 7 may also comprise storage means or a memory unit forstoring such a computer program and processing means or a processingunit, such as a microprocessor, for executing the computer program. Thestorage means may be a readable storage medium, but also a memorystorage unit 10 separated from, but connected to the signal conditioningunit 6 and the processing unit 7. When, in the following, it isdescribed that the IR camera 1, the signal conditioning unit 6 or theprocessing unit 7 performs a certain function or operation it is to beunderstood that the signal conditioning unit 6 and/or the processingunit 7 may use the processing means or logic to execute a certain partof the program which is stored in the storage means.

The processing unit 7 may also be connected to and/or arranged tocommunicate with a distance determining unit 8 arranged to determine thedistance between an object 3 in the imaged view 2 and the IR camera 1and output the measured distance to the processing unit 7. The distancedetermining unit 8 may, for example, be the at least one lensarrangement 4 using focusing operations to determine the distance to anobject 3, a laser distance measurement unit measuring the distance tothe object 3 using laser, or any other type of distance measuring unit.The processing unit 7 may also be connected to and/or arranged tocommunicate with at least one input control unit(s) 12 arranged toreceive manual inputs from a user of the IR camera 1 and output themanual inputs to the processing unit 7. The at least one input controlunit(s) 12 may, for example, be buttons and/or joysticks, or beincorporated in the IR camera display 11 as a touch screenfunctionality. The processing unit 7 may also be connected to and/orarranged to communicate with at least one temperature measurementunit(s) 13 arranged to measure the surrounding air temperature and/or asurface temperature and output the measured air temperature valuesand/or surface temperature values to the processing unit 7. The at leastone temperature measurement unit(s) 13 may be integrated into the IRcamera 1 (as shown in FIG. 1), or be comprised in a separate unitarranged to be connected to or communicate with the IR camera 1 from theoutside of the IR camera 1 (e.g. by wire or wirelessly). The at leastone temperature measurement unit(s) 13 may comprise an air temperaturemeasurement unit and/or a surface contact measuring unit. The processingunit 7 may also be connected to and/or arranged to communicate with awind speed measurement unit 15 arranged to measure the wind speed of theair surrounding the object 3 and output measured wind speed values tothe processing unit 7. The at least one air temperature measurementunit(s) 13 may be integrated into the IR camera 1 (as shown in FIG. 1),or be comprised in a separate unit arranged to be connected to orcommunicate with the IR camera 1 from the outside of the IR camera 1(e.g. by wire or wirelessly). The operation and use of the distancedetermining unit 8, the at least one input control unit(s) 12, the atleast one air temperature measurement unit(s) 13, and the wind speedmeasurement unit 15 are described in more detail in the exemplaryembodiments presented below with reference to FIGS. 2-5.

FIG. 2 shows an exemplary operation of the processing unit 7 in anembodiment of an IR camera 1. The processing unit 7 in the IR camera isarranged to perform calculations of power density values PD_(x,y) in theimaged view 2 indicative of an amount of energy dissipated in the imagedview 2 for temperature values of the thermal radiation data T_(x,y) byusing at least one determined temperature reference value.

By having the processing unit 7 in the IR camera 1 arranged to performcalculations of the power density values PD_(x,y), the IR camera 1 isable to calculate and/or display the power density distribution of animaged view 2. Thus, the IR camera 1 may increase usability to a user ofthe IR camera 1 when the user of the IR camera 1 is attempting toanalyze the imaged view 2 captured by the IR camera 1. This further mayallow a user of the IR camera 1 to achieve an estimate of the energyproperties of the imaged view 2 in a simple and easy manner withouthaving to perform any manual calculations of the same.

The processing unit 7 may be arranged to perform the calculation of thepower dissipated in the imaged view 2 (referred to herein as an outputpower values or output power density values, PD_(x,y)) based oncalculated values of the energy exchanged through radiation from asurface(s) in the imaged view 2 to its surrounding environment (referredto herein as the radiated power values, PD_(x,y) ^(rad)). This isillustrated by the logical block 21 in FIG. 2. The processing unit 7 mayfurther be arranged to perform the calculation of the output power valuePD_(x,y) based on the calculated value of the heat transfer due tonatural convection from a surface(s) in the imaged view 2 to itssurrounding environment (referred to herein as the convection powervalue, PD_(x,y) ^(conv)). This is illustrated by the logical block 22 inFIG. 2. As is illustrated by the logical block 23, the output powervalues PD_(x,y) may be calculated by the processing unit 7 according tothe following equation, Eq.1:PD _(x,y) =PD _(x,y) ^(rad) +PD _(x,y) ^(conv)  (Eq. 1)

Although the output power value PD_(x,y), according to Eq. 1 is usefulsince it sums the power outputted in the imaged view 2 through bothradiation and convection and thus may achieve a more accurate estimationof a value indicative of the outputted power in the imaged view, itshould be noted that the output power value PD_(x,y), may also becalculated by the processing unit 7 as either the radiated power valuePD_(x,y) ^(rad) or the convection power value, PD_(x,y) ^(conv).

The radiated power values PD_(x,y) ^(rad) in the imaged view 2 may becalculated in the logical block 21 by the processing unit 7 according tothe following equation, Eq.2:PD _(x,y) ^(rad)=ε·σ·((T _(x,y))⁴ −T _(rad,env) ⁴)  (Eq. 2)wherein

-   -   ε is the emissivity of the surface(s) in the imaged view 2,    -   σ is the Stefan-Boltzmann constant, 5.67·10⁻⁸ W/m²K⁴,    -   T_(x,y) is the temperature values at positions (x, y) in the        thermal radiation data received from the detector element 5 and        the signal conditioning unit 6,    -   T_(rad,env) is a temperature reference value representing the        temperature of the surrounding environment of the imaged view 2.

The convection power values PD_(x,y) ^(conv) in the imaged view 2 may becalculated in the logical block 22 by the processing unit 7 according tothe following equation, Eq.3:PD _(x,y) ^(conv) =h·(T _(x,y) −T _(conv,env))  (Eq. 3)wherein

-   -   h is a heat transfer coefficient [W/m²K],    -   T_(conv,env) is a temperature reference value representing the        temperature of the surrounding environment of the imaged view 2.

Thus, combining Eq.1-3, the output power values PD_(x,y) for each of thetemperature values of the thermal radiation data T_(x,y) may becalculated by the processing unit 7 according to the following equation,Eq. 4:PD _(x,y) =PD _(x,y) ^(rad) +PD _(x,y) ^(conv)=ε·σ·((T _(x,y))⁴ −T_(rad,env) ⁴)+h·(T _(x,y) −T _(conv,env))  (Eq. 4)

As the processing unit 7 in the IR camera 1 has calculated the outputpower values PD_(x,y) in accordance with the above, the processing unit7 may be arranged to control the IR camera display 11 to display thecalculated output power values PD_(x,y) to a user of the IR camera 1 inplace of the thermal images, e.g. as shown in FIG. 2. In the IR cameradisplay 11 shown in FIG. 2, the thermal image pixels in a first displayarea 24 show a first subset of the thermal image radiation data T_(x,y)for which the output power values PD_(x,y) are the same, for example, 28W/m². The IR camera display 11 may be arranged to present the outputpower values PD_(x,y) in IR camera display 11 in the similar manner asfor thermal image, such as, for example, using a colour palette toindicate different output power values PD_(x,y), and a indication scale27, etc. Furthermore, in the IR camera display 11 shown in FIG. 2, thethermal image pixels in a second display area 25 show a second subset ofthe thermal image radiation data T_(x,y) for which the output powervalues PD_(x,y) are the same, for example, 37 W/m², and the thermalimage pixels in a third display area 26 show a third subset of thethermal image radiation data T_(x,y) for which the output power valuesPD_(x,y) are the same, for example, 46 W/m². If the output power valuesPD_(x,y) are calculated by the processing unit 7 as either the radiatedpower values PD_(x,y) ^(rad) or the convection power values PD_(x,y)^(conv), the processing unit 7 may be arranged to control the IR cameradisplay 11 to also display information indicating to the user of the IRcamera 1 that this is the case. The processing unit 7 may also bearranged to store the output power values PD_(x,y) in the memory storageunit 10, for example, in order to perform post-processing of the outputpower values PD_(x,y).

However, in order for the processing unit 7 in the IR camera 1 tocalculate the output power values PD_(x,y) the parameters T_(rad,env),T_(conv,env), h and ε comprised in Eq. 1-4 have to be determined by theprocessing unit 7.

The temperature reference values T_(rad,env) and T_(conv,env)representing the temperature of the surrounding environment of theimaged view 2 may be determined by the processing unit 7 by receivinginformation from the input control unit(s) 12 comprising at least onetemperature value to be used as both or one of the temperature referencevalues T_(rad,env) and T_(conv,env). The user of the IR camera 1 maythus be arranged to manually enter a temperature value to the processingunit 7, which may be used by the processing unit 7 as both or one of thetemperature reference values T_(rad,env) and T_(conv,env).Alternatively, the processing unit 7 may be arranged to determine eitheror both of the temperature reference values T_(rad,env) and T_(conv,env)by receiving a temperature measurement value(s) from the temperaturemeasuring unit(s) 13. This alternative will also allow the processingunit 7 of the IR camera 1 to automatically determine either or both ofthe temperature reference values T_(rad,env) and T_(conv,env) to be usedin the calculation of the output power value PD_(x,y). Any one of thealternatives described above may be used by the processing unit 7 in theIR camera 1 in order to determine the temperature reference valueT_(rad,env) and/or the temperature reference value T_(conv,env).Alternatively, the IR camera 1 may use a surface temperature measurementunit arranged to detect a surface temperature for determining thetemperature reference value T_(rad,env), and a air temperaturemeasurement unit arranged to detect an air temperature for determiningthe temperature reference value T_(conv,env).

The heat transfer coefficient h indicates the amount of naturalconvection occurring at a surface(s) in the imaged view 2, and may bedetermined by the processing unit 7 by receiving information from theinput control unit(s) 12 comprising a heat transfer coefficient value.The heat transfer coefficient value may be inputted manually by a userof the IR camera 1. Alternatively, the heat transfer coefficient valuemay be based on information indicating the wind speed of the airsurrounding the imaged view 2 received from the wind speed measuringunit 15. For a particular wind speed, the processing unit 7 maydetermine a corresponding heat transfer coefficient value to be used bythe processing unit when calculating the output power values PD_(x,y).This may be performed by the processing unit 7 or the memory storageunit 10 comprising a list associating wind speeds with correspondingheat transfer coefficient values. The heat transfer coefficient valuemay also be set to a suitable default value, such as, for example,1≦h≦10 for indoor environments, and 1≦h≦100 for outdoor environments.

The emissivity ε of surface(s) in the imaged view 2 may be determined bythe processing unit 7 by receiving information from the input controlunit(s) 12 comprising a value of the emissivity of the surface(s). Thevalue of the emissivity ε of the surface(s) may be inputted manually bya user of the IR camera 1. The value of the emissivity ε may also be setto a suitable default value, for example, ε=1.

FIG. 3 shows another exemplary operation of the processing unit 7 in anembodiment of an IR camera 1. As will become apparent in the following,by using information received from the signal conditioning unit 6, thedistance determining unit 8, the memory storage 10, the input controlunit(s) 12, the temperature measurement unit(s) 13, and/or the windspeed measurement unit 15, the processing unit 7 in the IR camera 1 isarranged to perform calculations of the power which is outputted from anobject 3 in the imaged view 2. The power outputted from the object 3 mayalso be referred to as the total heat loss of the object 3 as viewed bythe IR camera 1.

By having the processing unit 7 in the IR camera 1 arranged to performcalculations of the power which is outputted from an object 3 in theimaged view 2, the IR camera 1 may increase usability to a user of theIR camera 1 when the user of the IR camera 1 is attempting to analyzethe object 3 by viewing the thermal images of the IR camera 1. This mayallow a user of the IR camera 1 to achieve an estimate of the energyproperties of the imaged object 3 in a simple and easy manner withouthaving to perform any manual calculations of the same.

The processing unit 7 may be arranged to perform the calculation of thepower outputted from an object 3 in the imaged view 2 (referred toherein as an object output power value, P_(TOT) ^(obj)) based on acalculated value of the energy exchanged by the object 3 throughradiation from its surface to its surrounding environment (referred toherein as the radiated power value, P_(rad) ^(obj)). This is illustratedby the logical block 31 in FIG. 3. The processing unit 7 may further bearranged to perform the calculation of the object output power valueP_(TOT) ^(obj) based on the calculated value of the heat transfer due tonatural convection from the object 3 to its surrounding environment(referred to herein as the convection power value, P_(conv) ^(obj)).This is illustrated by the logical block 32 in FIG. 3. As is illustratedby the logical block 33 and as shown in FIG. 3 (e.g., in a displaywindow 34 in IR camera display 11), the object output power valueP_(TOT) ^(obj), may be calculated by the processing unit 7 according tothe following equation, Eq.5:P _(TOT) ^(obj) =P _(rad) ^(obj) +P _(conv) ^(obj)  (Eq.5)

Although the object output power value P_(TOT) ^(obj) according to Eq. 1is useful since it sums the power outputted from the object 3 throughboth radiation and convection and may thus achieve a more accurateestimation of a value of the outputted power from the object 3. Itshould be noted that the object output power value P_(TOT) ^(obj) mayalso be calculated by the processing unit 7 as either the radiated powervalue P_(rad) ^(obj) or the convection power value, P_(conv) ^(obj).

The radiated power value P_(rad) ^(obj) from the object 3 in the imagedview 2 may be calculated in the logical block 31 by the processing unit7 according to the following equation, Eq. 6:

$\begin{matrix}{P_{rad}^{obj} = {{ɛ \cdot A \cdot \sigma \cdot {\sum\limits_{x,y}\left( T_{x,y}^{obj} \right)^{4}}} - T_{{rad},{env}}^{4}}} & \left( {{Eq}.\mspace{14mu} 6} \right)\end{matrix}$wherein

-   -   ε is the emissivity of the surface of the object 3,    -   A is the surface area of the object 3 facing towards and being        perceived by 2D-camera view of the IR camera 1,    -   σ is the Stefan-Boltzmann constant, 5.67·10⁻⁸ W/m²K⁴,    -   T_(x,y) ^(obj) is a first subset of the thermal radiation data        T_(x,y) received from the detector element 5 and the signal        conditioning unit 6 which has been determined by the processing        unit 7 to represent the object 3 in the imaged view 2 (herein        referred to as the thermal image object area 35) for which an        object output power value P_(TOT) ^(obj) is to be determined,    -   T_(rad,env) is a temperature reference value representing the        temperature of the surrounding environment of the object 3 in        the imaged view 2.

The convection power value P_(conv) ^(obj) from the object 3 in theimaged view 2 may be calculated in the logical block 32 by theprocessing unit 7 according to the following equation, Eq. 7:

$\begin{matrix}{P_{conv}^{obj} = {{A \cdot h \cdot {\sum\limits_{x,y}T_{x,y}^{obj}}} - T_{{conv},{env}}}} & \left( {{Eq}.\mspace{14mu} 7} \right)\end{matrix}$wherein

-   -   h is a heat transfer coefficient [W/m²K],    -   T_(conv,env) is a temperature reference value representing the        temperature of the surrounding environment of the object 3 in        the imaged view 2.

Thus, combining Eq.1-3, the object output power value P_(TOT) ^(obj) maybe calculated by the processing unit 7 according to the followingequation, Eq. 8:

$\begin{matrix}{P_{TOT}^{obj} = {{P_{rad}^{obj} + P_{conv}^{obj}} = {{{ɛ \cdot A \cdot \sigma \cdot {\sum\limits_{x,y}\left( {\left( T_{x,y}^{obj} \right)^{4} - T_{{rad},{env}}^{4}} \right)}} + {A \cdot h \cdot {\sum\limits_{x,y}\left( {T_{x,y}^{obj} - T_{{conv},{env}}} \right)}}} = {A \cdot \left( {{ɛ \cdot \sigma \cdot {\sum\limits_{x,y}\left( {\left( T_{x,y}^{obj} \right)^{4} - T_{{rad},{env}}^{4}} \right)}} + {h \cdot {\sum\limits_{x,y}\left( {T_{x,y}^{obj} - T_{{conv},{env}}} \right)}}} \right)}}}} & \left( {{Eq}.\mspace{14mu} 8} \right)\end{matrix}$

As the processing unit 7 in the IR camera 1 has calculated the objectoutput power value P_(TOT) ^(obj) in accordance with the above, theprocessing unit 7 may be arranged to control the IR camera display 11 todisplay the object output power value P_(TOT) ^(obj) to a user of the IRcamera 1 together with the thermal images, e.g. as shown in FIG. 1. Ifthe object output power value P_(TOT) ^(obj) is calculated by theprocessing unit 7 as either the radiated power value P_(rad) ^(obj) orthe convection power value, P_(conv) ^(obj), the processing unit 7 maybe arranged to control the IR camera display 11 to also displayinformation indicating to the user of the IR camera 1 that this is thecase.

As can be seen from Eq. 1-4 in the previous embodiment described inreference to FIG. 2 and Eq. 9 below, the object output power valueP_(TOT) ^(obj) indicative of the amount of energy outputted from theobject 3 in the imaged view 2 can be said to be based upon output powervalues PD_(x,y) belonging to the determined thermal image object area 35in the thermal radiation data T_(x,y) which may referred to as objectoutput power density values PD_(x,y) ^(obj). The object output powerdensity values PD_(x,y) ^(obj) can be said to comprise power densityvalues in W/m² for temperature values in the thermal radiation dataT_(x,y) which when summed over a defined area, such as, the thermalimage object area 35 of the object 3, results in an object output powervalue P_(TOT) ^(obj) in W.

$\begin{matrix}{P_{TOT}^{obj} = {{P_{rad}^{obj} + P_{conv}^{obj}} = {{{ɛ \cdot A \cdot \sigma \cdot {\sum\limits_{x,y}\left( {\left( T_{x,y}^{obj} \right)^{4} - T_{{rad},{env}}^{4}} \right)}} + {A \cdot h \cdot {\sum\limits_{x,y}\left( {T_{x,y}^{obj} - T_{{conv},{env}}} \right)}}} = {{A \cdot \left( {{ɛ \cdot \sigma \cdot {\sum\limits_{x,y}\left( {\left( T_{x,y}^{obj} \right)^{4} - T_{{rad},{env}}^{4}} \right)}} + {h \cdot {\sum\limits_{x,y}\left( {T_{x,y}^{obj} - T_{{conv},{env}}} \right)}}} \right)} = {A \cdot {\sum\limits_{x,y}{PD}_{x,y}^{obj}}}}}}} & \left( {{Eq}.\mspace{14mu} 9} \right)\end{matrix}$

However, in order for the processing unit 7 in the IR camera 1 tocalculate the object output power value P_(TOT) ^(obj) the parametersT_(x,y) ^(obj), or PD_(x,y) ^(obj), and A comprised in Eq. 5-9 have tobe determined by the processing unit 7. The parameters T_(rad,env),T_(conv,env), h and ε may be determined by the processing unit 7 in thesame manner as described in the previous embodiment described inrelation to FIG. 2.

The first subset T_(x,y) ^(obj) of the thermal radiation data T_(x,y)corresponds to a thermal image object area 35 in the thermal imagesdisplayed on the display unit 11. The thermal image object area 35represents the object 3 in the imaged view 2 for which an output powervalue P_(TOT) ^(obj) is to be determined. The thermal image object area35 may be determined by the processing unit 7 by receiving informationfrom the input control unit(s) 12 indicating a particular area in thethermal images displayed on the display unit 11 as the thermal imageobject area 35. By receiving the information indicating a particulararea as the thermal image object area 35, the processing unit 7 mayidentify the first subset T_(x,y) ^(obj) of the thermal radiation dataT_(x,y) corresponding to the indicated thermal image object area 35. Forexample, the user of the IR camera 1 may, using the input controlunit(s) 12, place a digital marker or indicator around the particulararea in the thermal images to be indicated as the thermal image objectarea 35 in the thermal images. Alternatively, the thermal image objectarea 35 and the corresponding first subset T_(x,y) ^(obj) of the thermalradiation data T_(x,y) may be determined by the processing unit 7 byusing a temperature threshold value. The temperature threshold valuewill directly indicate a first subset T_(x,y) ^(obj) of the thermalradiation data T_(x,y) as the thermal image object area 35. Thetemperature threshold value may be a user-settable threshold value or adefault threshold value. The user of the IR camera 1 may set thetemperature threshold value to be used in determining the thermal imageobject area 35 and the corresponding first subset T_(x,y) ^(obj) of thethermal radiation data T_(x,y) by using the input control unit(s) 12.The same procedures may be used in order to determine the object outputpower density values PD_(x,y) ^(obj) from which the object output powervalue P_(TOT) ^(obj) may be calculated as well.

The temperature reference values T_(rad,env) and T_(conv,env)representing the temperature of the surrounding environment of theobject 3 in the imaged view 2 may be determined by the processing unit 7in the same manner as described in the previous embodiment described inrelation to FIG. 2. However, alternatively the processing unit 7 mayhere be arranged to determine a second subset T_(x,y) ^(ref) of thethermal radiation data T_(x,y) as a thermal image reference area 36(shown in FIG. 3). The thermal image reference area 36 may be determinedby the processing unit 7 as the part of the thermal radiation dataT_(x,y) that is not a part of the determined thermal image object area35 in the thermal radiation data T_(x,y), i.e. the first subset T_(x,y)^(obj) of the thermal radiation data T_(x,y). By calculating antemperature value representative for the determined thermal imagereference area 36 in the thermal radiation data T_(x,y), the processingunit 7 may determine either or both of the temperature reference valuesT_(rad,env) and T_(conv,env) as the representative temperature valueobtained for the thermal image reference area 36 in the thermalradiation data T_(x,y). The representative temperature value of thethermal image reference area 36 may, for example, be calculated by theprocessing unit 7 as median or mean value of the thermal radiation dataT_(x,y) in the determined thermal image reference area 36. Thisalternative allows the processing unit 7 of the IR camera 1 toautomatically determine either or both of the temperature referencevalues T_(rad,env) and T_(conv,env) to be used in the calculation of theobject output power value P_(TOT) ^(obj).

The surface area parameter A represents the actual surface area of theobject 3 facing towards and being perceived by 2D-camera view of the IRcamera 1 in the imaged view 2. The surface area parameter A may bedetermined by the processing unit 7 by receiving information from theinput control unit(s) 12 comprising a value of the actual physicalsurface area of the object 3. The user of the IR camera 1 may thus bearranged to manually enter an area value to the processing unit 7corresponding to the surface of the object 3, which may be used by theprocessing unit 7 as a value of the surface area parameter A. The valueof the surface area parameter A may also be set to a suitable defaultvalue.

Alternatively, the processing unit 7 may be arranged to receiveinformation from the distance determining unit 8 comprised in the IRcamera 1, wherein the information comprises a distance d between theactual physical object 3 in the imaged view 2 and the IR camera 1.Further, the processing unit 7 may be arranged to determine an objectfield-of-view o_(fov) 14 of the determined thermal image object area 35in the thermal radiation data T_(x,y). An object field-of-view o_(fov)14 of a determined thermal image object area 35 in the thermal radiationdata T_(x,y) may be determined by the processing unit 7 by, for example,from the first subset T_(x,y) ^(obj) of the thermal radiation dataT_(x,y) determined as the thermal image object area 35, determine howmuch of the total field-of-view 2 of the IR camera 1, i.e. the entirethermal radiation data T_(x,y) T is occupied by the thermal image objectarea 35 and then, since the total field-of-view of the IR camera 1 isdetermined by the type of components incorporated in the IR camera 1 andhence may be known by the processing unit 7, estimate the objectfield-of-view o_(fov) 14 based upon how much of the total field-of-viewof the IR camera 1 is occupied by the thermal image object area 35. Oncethe distance d to the object 3 has been received and the objectfield-of-view o_(fov) 14 has been determined, the processing unit 7 maycalculate an estimate of the actual physical surface area of the object3 in the imaged view 2 facing towards and being perceived by 2D-cameraview of the IR camera 1, i.e. the surface area parameter A, based uponthe received distance d to the object 3 and the determined objectfield-of-view o_(fov) 14. For example, this may be performed by theprocessing unit 7 by using the area a_(x,y) ^(pix) for each thermalimage pixel in the object field-of-view o_(fov) 14 of the determinedthermal image object area 35 according to the following equation, Eq.10-11:

$\begin{matrix}{a_{x,y}^{pix} = \left( {2 \cdot d \cdot {\tan\left( \frac{o_{fov}^{pix}}{2} \right)}} \right)^{2}} & \left( {{Eq}.\mspace{14mu} 10} \right) \\{A = {\sum\limits_{x,y}a_{x,y}^{pix}}} & \left( {{Eq}.\mspace{14mu} 11} \right)\end{matrix}$

The field-of-view for each pixel o_(fov) ^(pix) in the objectfield-of-view o_(fov) 14 of the determined thermal image object area 35may, for example, by dividing the total field-of-view of the IR camera 1by the resolution of the detector element 5 in the IR camera 1.

According to another alternative, the processing unit 7 may be arrangedto receive information from the input control unit(s) 12 which comprisesa form indicator f_(ind). The form indicator f_(ind) may be indicativeof the shape or form of the actual physical object 3 in the imaged view2. The form indicator f_(ind) may be used to describe and represent theactual shape, form and/or orientation of the surface of the object 3facing and being perceived by 2D-camera view of the IR camera 1.Furthermore, if the object 3 in the imaged view 2 can be assumed to emitenergy homogenously in every direction and the object output power valueP_(TOT) ^(obj) is to be determined for the entire object 3, that is, notonly for the surface of the object 3 facing and being perceived by2D-camera view of the IR camera 1, the form indicator f_(ind) may beused to describe and represent the 3D-shape or form of the object 3 inthe imaged view 2. The form indicator f_(ind), or a corresponding valuestored for the particular form indicator in the memory storage unit 10or in the processing unit 7, may be used by the processing unit 7 whencalculating the object output power value P_(TOT) ^(obj). For example,this may be performed by the processing unit 7 by modifying Eq.11according to the following equation, Eq. 12:

$\begin{matrix}{A = {f_{ind} \cdot {\sum\limits_{x,y}a_{x,y}^{pix}}}} & \left( {{Eq}.\mspace{14mu} 12} \right)\end{matrix}$

Thus, the form indicator f_(ind) may be used to adapt the surface areaparameter according to the actual 3D shape and form of the object 3 inthe imaged view 2.

The form indicator f_(ind) may be manually inputted by the user of theIR camera 1 through the input control unit(s) 12. However, the user ofthe IR camera 1 may also be presented in the display unit 11 with arange of alternative object views from which the user of the IR camera 1may select the most suitable alternative using the input control unit(s)12, whereby the form indicator f_(ind) associated with the selectedobject view may be used by the processing unit 7 when calculating theobject output power value P_(TOT) ^(obj). The alternative object viewsmay, for example, be images describing different geometric forms and/orthe angle from which the object 3 having a particular geometric form isviewed by the IR camera 1.

According to yet another alternative, if the distance d comprised ininformation received from the distance determining unit 8 is a distancemap, the processing unit 7 may be arranged to estimate the shape or formof the actual physical object 3 in the imaged view 2 using this distancemap. The distance map comprise separate distance values for differentsubsets of the thermal radiation data T_(x,y), for example, one distancevalue for each captured temperature value by the detector element 5. Byreceiving the distance map from the distance determining unit 8, theprocessing unit 7 may determine the distances to each temperature valuein the first subset T_(x,y) ^(obj) of the thermal radiation data T_(x,y)corresponding to the thermal image object area 35. The processing unit 7is thus able to achieve a 3D-representation of the object 3 in theimaged view 2 and may use the 3D-representation of the object 3 whencalculating the object output power value P_(TOT) ^(obj). This may, forexample, be performed by the processing unit 7 by determining a suitableform indicator f_(ind) to be used in dependence of the 3D-representationof the object 3, or by comprising an area estimation algorithm which mayestimate the surface area of the object 3 using the 3D-representation ofthe object 3. This may be performed for the surface of the object 3facing and being perceived by 2D-camera view of the IR camera 1. Forexample, the processing unit 7 may be arranged to incorporate the3D-representation of the object 3 in Eq. 8 by having the area a_(x,y)^(pix) for each thermal image pixel in the object field-of-view o_(fov)14 of the determined thermal image object area 35 included incalculation of the object output power value P_(TOT) ^(obj) according tothe following equation, Eq. 13:

$\begin{matrix}{P_{TOT}^{obj} = {{ɛ \cdot \sigma \cdot {\sum\limits_{x,y}{a_{x,y} \cdot \left( {\left( T_{x,y}^{obj} \right)^{4} - T_{{rad},{env}}^{4}} \right)}}} + {h \cdot {\sum\limits_{x,y}{a_{x,y} \cdot \left( {T_{x,y}^{obj} - T_{{conv},{env}}} \right)}}}}} & \left( {{Eq}.\mspace{14mu} 13} \right)\end{matrix}$wherein a_(x,y) ^(pix) is dependent upon its corresponding value d inthe distance map.

The processing unit 7 may be arranged to combine the use of a formindicator f_(ind) according to the previous alternative (for example, todetermine an object output power value P_(TOT) ^(obj) for the entireobject 3, that is, not only for the surface of the object 3 facing andbeing perceived by 2D-camera view of the IR camera 1) with a formindicator f_(ind), or 3D representation, according to the latteralternative (for example, to determine the surface of the object 3facing and being perceived by 2D-camera view of the IR camera 1) whencalculating the object output power value P_(TOT) ^(obj).

FIG. 4 shows an exemplary operation of the processing unit 7 in anotherembodiment of an IR camera 1. The processing unit 7 according to thisembodiment is identical to the processing unit 7 according the previousembodiment, except that the processing unit 7 further comprises thefunctionality of the logical block 41. The processing unit 7 in the IRcamera 1 may be arranged to receive information comprising the currentenergy price information c_(meas) and/or a time span informationt_(meas) from the input control unit(s) 12. The current energy priceinformation c_(meas) and/or a time span information t_(meas) may beinputted manually by a user of the IR camera 1. The current energy priceinformation c_(meas) is a value that relates the object output powervalue P_(TOT) ^(obj) accumulated over time to an actual energy cost forhaving the object 3 emitting that amount of energy during that time. Thetime span information t_(meas) may be obtained by having the processingunit 7 start a time span measurement when a user of the IR camera 1indicates to the processing unit 7 using the input control unit(s) 12that the object output power calculation according to the above shouldbegin and stop the time span measurement when the user of the IR camera1 indicates to the processing unit 7 using the input control unit(s) 12that the object output power calculation according to the above shouldstop. The time span information t_(meas) may also be provided to theprocessing unit 7 after the object output power calculation by theprocessing unit 7 has been performed over a particular time period,whereby the time span information t_(meas) may indicate a subset of thatparticular time period. The time span information t_(meas) may be usedby the processing unit 7 for calculating a total energy output valueE_(TOT) ^(obj) for the object 3 in the imaged view 2. The processingunit 7 may calculate a total energy output value E_(TOT) ^(obj) for theobject 3 in the imaged view 2 based on the time span informationt_(meas) and the calculated object output power value P_(TOT) ^(obj)according to the following equation, Eq. 14:

$\begin{matrix}{E_{TOT}^{obj} = {\int_{t_{1} = 0}^{t_{2} = t_{meas}}{{P_{TOT}^{obj}(t)}{\mathbb{d}t}}}} & \left( {{Eq}.\mspace{14mu} 14} \right)\end{matrix}$

Alternatively, the processing unit 7 may calculate a total energy outputvalue E_(TOT) ^(obj) for the object 3 in the imaged view 2 based on thetime span information t_(meas)=Δt and the calculated object output powervalue P_(TOT) ^(obj) according to the following equation, Eq. 15:E _(TOT) ^(obj) =P _(TOT) ^(obj) ·Δt  (Eq. 15)wherein P_(TOT) ^(obj) is assumed to be constant over time.

The processing unit 7 may calculate a total energy cost value C based onthe current energy price information c_(meas) and the total energyoutput value E_(TOT) ^(obj) according to the following equation, Eq. 16:

$\begin{matrix}{C = {{c_{meas} \cdot E_{TOT}^{obj}} = {c_{meas} \cdot {\int_{t_{1} = 0}^{t_{2} = t_{meas}}{{P_{TOT}^{obj}(t)}{\mathbb{d}t}}}}}} & \left( {{Eq}.\mspace{14mu} 16} \right)\end{matrix}$

The total energy cost value C may also be calculated using Eq.15.

The processing unit 7 may then control the IR camera display 11 todisplay the total energy cost value (as shown in FIG. 4) and/or thetotal energy output value E_(TOT) ^(obj) to a user of the IR camera 1together with the thermal images. The displayed total energy cost value(as shown in FIG. 4) and/or total energy output value E_(TOT) ^(obj) mayalso be displayed in the display unit 11 a running value that iscontinuously updated for an time span that has begun, but not beenstopped yet. The displayed total energy cost value (as shown in FIG. 4)and/or total energy output value E_(TOT) ^(obj) may also be displayed inthe display unit 11 in a separate indicator window 42. This enables asimple and clear identification of the total energy cost value (as shownin FIG. 4) and/or total energy output value E_(TOT) ^(obj) by the userof the IR camera 1.

FIG. 5 is a flowchart illustrating a method to be used in a processingunit 7 in an exemplary embodiment of an IR camera 1. In step S51, theprocessing unit 7 may determine at least one temperature referencevalue. The at least one temperature reference value may represent thetemperature of the surrounding environment of an imaged view in the IRcamera. In step S52, the processing unit 7 may calculate at least oneoutput power value using the temperature value of the thermal radiationdata corresponding to a part of the imaged view and the at least onedetermined temperature reference value. The at least one output powervalue being indicative of an amount of energy dissipated in that part ofthe imaged view. The method described in reference to FIG. 5 may furtherinclude the step of controlling an IR camera display to display the atleast one calculated output power value to a user of the IR camera inplace of the corresponding temperature pixel in the thermal image.

FIG. 6 is a flowchart illustrating a method to be used in a processingunit 7, as described with respect to FIG. 3, in an exemplary embodimentof an IR camera 1. Step S61 is identical to step S51 described above. Instep S62, the processing unit 7 may determine a thermal image objectarea in the thermal radiation data. This may be performed by determininga first subset of the thermal radiation data as a thermal image objectarea representing an object in the imaged view for which an output powervalue is to be determined. In step S63, the processing unit 7 maycalculate an object output power value. This may be performed bycalculating an object output power value indicative of the amount ofenergy outputted from the object in the imaged view based upon outputpower values of the determined thermal image object area in the thermalradiation data. The method described in reference to FIG. 6 may furtherinclude the step of controlling the IR camera display to display thecalculated object output power value to a user of the IR camera togetherwith the thermal images.

FIG. 7 is a flowchart illustrating a method according to an exemplaryembodiment. Step S71-S73 is identical to the steps S61-S63 according tothe above.

In step S74, the processing unit 7 may receive a time span and currentenergy price information. In step S75, the processing unit 7 maycalculate a total energy cost value. This may be performed bycalculating a total energy output value for the object in the imagedview based on the time span information and the calculated object outputpower value, and by then calculating a total energy cost value based onthe current energy price information and the calculated total energyoutput value. The method according to FIG. 5 may further include thestep of controlling the IR camera display to display total energy costvalue and/or the total energy output value to a user of the IR cameratogether with the thermal images.

The description is not intended to be taken in a limiting sense, but ismade merely for the purpose of describing the general principles ofseveral optional embodiments. The scope of the invention should only beascertained with reference to the issued claims.

1. An IR camera comprising: a thermal radiation capturing arrangementfor capturing thermal radiation of an imaged view in response to aninput control unit(s) receiving inputs from a user of the IR camera; aprocessing unit arranged to process the thermal radiation data (T_(x,y))in order for the thermal radiation data (T_(x,y)) to be displayed by anIR camera display as thermal images; and an IR camera display arrangedto display thermal images to a user of the IR camera; wherein theprocessing unit is further arranged to: determine at least onetemperature reference value (T_(rad,env), T_(conv,env)) representing thetemperature of the surrounding environment of the imaged view; calculateat least one output power value (PD_(x,y)) indicative of an amount ofenergy dissipated in a part of the imaged view by using the temperaturevalue of the thermal radiation data (T_(x,y)) corresponding to said partof the imaged view and the at least one determined temperature referencevalue (T_(rad,env), T_(conv,env)); determine a first subset (T_(x,y)^(obj)) of the thermal radiation data (T_(x,y)) as a thermal imageobject area representing an object in the imaged view for which anoutput power value (P_(TOT) ^(obj)) is to be determined; and calculatean object output power value (P_(TOT) ^(obj)) indicative of the amountof energy dissipated from the object in the imaged view based uponoutput power values (PD_(x,y)) of the determined thermal image objectarea in the thermal radiation data (T_(x,y)).
 2. An IR camera accordingto claim 1, wherein the processing unit is arranged to control the IRcamera display to display the at least one calculated output power value(PD_(x,y)) to a user of the IR camera in place of the correspondingtemperature pixel in the thermal image.
 3. An IR camera according toclaim 1, wherein the processing unit is arranged to control the IRcamera display to display the calculated object output power value(P_(TOT) ^(obj)) to a user of the IR camera together with the thermalimages.
 4. An IR camera according to claim 1, wherein the processingunit is further arranged to: receive information comprising currentenergy price information (c_(meas)) and/or time span information(t_(meas)); calculate a total energy output value (E_(TOT) ^(obj)) forthe object in the imaged view based on the time span information(t_(meas)) and the calculated object output power value (P_(TOT)^(obj)); calculate a total energy cost value (C) based on the currentenergy price information (c_(meas)) and the total energy output value(E_(TOT) ^(obj)); and control the IR camera display to display the totalenergy cost value (C) and/or the total energy output value (E_(TOT)^(obj)) to a user of the IR camera together with the thermal images. 5.An IR camera according to claim 1, wherein the processing unit isarranged to determine the thermal image object area by receivinginformation from the input control unit(s) indicating the first subset(T_(x,y) ^(obj)) of the thermal radiation data (T_(x,y)) as the thermalimage object area.
 6. An IR camera according to claim 1, wherein theprocessing unit is arranged to determine the thermal image object areaby using a temperature threshold value to indicate the first subset(T_(x,y) ^(obj)) of the thermal radiation data (T_(x,y)) as the thermalimage object area (A).
 7. An IR camera according to claim 1, wherein theprocessing unit is arranged to: receive, from the input control unit(s),information comprising a value of an actual physical surface area of theobject in the imaged view facing towards the IR camera; and use thisinformation when calculating the object output power value (P_(TOT)^(obj)).
 8. An IR camera according to claim 1, wherein the processingunit is arranged to: receive, from a distance determining unit comprisedin the IR camera, information comprising a distance between the actualphysical object captured in the imaged view and the IR camera; determinean object field-of-view (o_(fov)) of the determined thermal image objectarea (A) in the thermal radiation data (T_(x,y)); estimate an actualphysical surface area of the object in the imaged view facing towardsthe IR camera based upon the received distance and the determined objectfield-of-view (o_(fov)); and use the estimation of the actual physicalsurface area of the object in the imaged view when calculating theobject output power value (P_(TOT) ^(obj)).
 9. An IR camera according toclaim 8, wherein the processing unit is further arranged to: receive,from the input control unit(s), information comprising a form indicatorwhich is indicative of the shape or form of the actual physical objectin the imaged view; and use the form indicator or a corresponding valuewhen calculating the object output power value (P_(TOT) ^(obj)).
 10. AnIR camera according to claim 8, wherein: the distance comprised in theinformation from the distance determining unit is a distance mapcomprising separate distance values for different subsets of the thermalradiation data (T_(x,y)); and the processing unit is arranged to:estimate the shape or form of the actual physical object in the imagedview using the distance map, and use this estimate or a correspondingvalue when calculating the object output power value (P_(TOT) ^(obj)).11. An IR camera according to claim 1, wherein the processing unit isarranged to determine the at least one temperature reference value(T_(rad,env), T_(conv,env)) by receiving information from the inputcontrol unit(s) comprising a temperature value(s) to be used as the atleast one temperature reference value (T_(rad,env), T_(conv, env)). 12.An IR camera according to claim 1, wherein the processing unit isarranged to: determine a second subset (T_(x,y) ^(ref)) of the thermalradiation data (T_(x,y)) as a thermal image reference area, wherein thethermal image reference area is not part of the determined thermal imageobject area in the thermal radiation data (T_(x,y)); calculate anrepresentative temperature value for the thermal image reference area inthe thermal radiation data (T_(x,y)); and use the representativetemperature value for the thermal image reference area in the thermalradiation data (T_(x,y)) as the at least one temperature reference value(T_(rad,env), T_(conv,env)) when determining the at least onetemperature reference value (T_(rad,env), T_(conv,env)).
 13. An IRcamera according to claim 1, wherein the processing unit is arranged todetermine the at least one temperature reference value (T_(rad,env),T_(conv,env)) by receiving temperature value(s) from at least onetemperature measuring unit comprised in the IR camera.
 14. A method foruse in a processing unit of an IR camera capturing thermal radiationdata (T_(x,y)) of an imaged view, the method comprising: determining atleast one temperature reference value (T_(rad,env), T_(conv,env))representing the temperature of the surrounding environment of theimaged view; calculating at least one output power value (PD_(x,y))indicative of an amount of energy dissipated in a part of the imagedview by using the temperature value of the thermal radiation data(T_(x,y)) corresponding to said part of the imaged view and the at leastone determined temperature reference value (T_(rad,env), T_(conv,env));determining a first subset (T_(x,y) ^(obj)) of the thermal radiationdata (T_(x,y)) as a thermal image object area (A) representing an objectin the imaged view for which an output power value (P_(TOT) ^(obj)) isto be determined; and calculating an object output power value (P_(TOT)^(obj)) indicative of the amount of energy dissipated from the object inthe imaged view based upon output power values (PD_(x,y)) of thedetermined thermal image object area in the thermal radiation data(T_(x,y)).
 15. A method according to claim 14, further comprising:controlling an IR camera display of the IR camera to display the atleast one calculated output power value (PD_(x,y)) to a user of the IRcamera in place of the corresponding temperature pixel in the thermalimage.
 16. A method according to claim 14, further comprisingcontrolling an IR camera display of the IR camera to display thecalculated object output power value (P_(TOT) ^(obj)) to a user of theIR camera together with the thermal images.
 17. A method according toclaim 14, further comprising: receiving information comprising currentenergy price information (c_(meas)) and/or time span information(t_(meas)); calculating a total energy output value (E_(TOT) ^(obj)) forthe object in the imaged view based on the time span information(t_(meas)) and the calculated object output power value (P_(TOT)^(obj)); calculating a total energy cost value (C) based on the currentenergy price information (c_(meas)) and the total energy output value(E_(TOT) ^(obj)); and controlling an IR camera display of the IR camerato display total energy cost value (C) and/or the total energy outputvalue (E_(TOT) ^(obj)) to a user of the IR camera together with thethermal images.
 18. A non-transitory computer-readable medium storing aplurality of computer-readable instructions which, when executed by aprocessing unit in an IR camera, cause said processing unit in the IRcamera to perform a method comprising: determining at least onetemperature reference value (T_(rad,env), T_(conv,env)) representing thetemperature of the surrounding environment of the imaged view;calculating at least one output power value (PD_(x,y)) indicative of anamount of energy dissipated in a part of the imaged view by using thetemperature value of the thermal radiation data (T_(x,y)) correspondingto said part of the imaged view and the at least one determinedtemperature reference value (T_(rad,env), T_(conv,env)); determining afirst subset (T_(x,y) ^(obj)) of the thermal radiation data (T_(x,y)) asa thermal image object area (A) representing an object in the imagedview for which an output power value (P_(TOT) ^(obj)) is to bedetermined; and calculating an object output power value (P_(TOT)^(obj)) indicative of the amount of energy dissipated from the object inthe imaged view based upon output power values (PD_(x,y)) of thedetermined thermal image object area in the thermal radiation data(T_(x,y)).
 19. A non-transitory computer-readable medium according toclaim 18, wherein the method further comprises controlling an IR cameradisplay of the IR camera to display the at least one calculated outputpower value (PD_(x,y)) to a user of the IR camera in place of thecorresponding temperature pixel in the thermal image.
 20. Anon-transitory computer-readable medium according to claim 18, whereinthe method further comprises controlling an IR camera display of the IRcamera to display the calculated object output power value (P_(TOT)^(obj)) to a user of the IR camera together with the thermal images. 21.A non-transitory computer-readable medium according to claim 18, whereinthe method further comprises: receiving information comprising currentenergy price information (C_(meas)) and/or time span information(t_(meas)); calculating a total energy output value (E_(TOT) ^(obj)) forthe object in the imaged view based on the time span information(t_(meas)) and the calculated object output power value (P_(TOT)^(obj)); calculating a total energy cost value (C) based on the currentenergy price information (c_(meas)) and the total energy output value(E_(TOT) ^(obj)); and controlling an IR camera display of the IR camerato display total energy cost value (C) and/or the total energy outputvalue (E_(TOT) ^(obj)) to a user of the IR camera together with thethermal images.